Why So Many of Us Die of Heart Disease
Haider Warraich, a fellow in cardiovascular medicine at the Duke University Medical Center (and an occasional Atlantic contributor), is at work on a book about how heart disease came to be such a big threat to humanity. We recently spoke about some of the insights he’s come across in his research and practice. An edited transcript of the conversation follows.
Olga Khazan: So, you say evolution is the main reason you see a lot of heart disease in humans. Why is that?
Haider Warraich: If you look back and see what it was that has threatened human beings for more than 95 percent of our existence, it’s been three main things: infections, injuries or wounds, and malnutrition. In that setting, the most successful human being was the one who had the most paranoid and xenophobic immune system, which would detect any outside activity and then try to destroy it as soon as possible.
Now, that of course, has changed. We don’t have the burden of infections, especially in higher-income countries, but what has happened is that we have been self-selected to have a very, very robust immune system.
For most of human history, things like being bitten by some wild animal or having any type of traumatic injury has been a part of routine human life. The way that we’ve always combated that has been with inflammation. When the immune system is activated, it results in inflammation. For example, you get a viral infection and you have a fever. That fever is really as a result of the inflammation that’s being caused by the immune system.
What we’re learning is that inflammation is in fact at the heart of atherosclerosis, which is basically at the heart of all heart disease, stroke, and heart attacks. White blood cells, many of them, are full of cholesterol, and they’ll start depositing. Over time, as these plaques build up, they result in blockages that can lead to heart attacks and strokes.
These very robust immune systems are in some ways like a post–Cold War nuclear arsenal, in which you don’t have that threat anymore, but these weapons are still lying around. That’s why we see all these autoimmune diseases, and also we see such a high prevalence of atherosclerosis.
[In a similar way,] even though our nutrition has changed a lot, adaptive mechanisms that were meant to protect us from starvation have now, in fact, led to the dual epidemics of obesity and diabetes, which are some of the main reasons why heart disease remains the number-one killer of people around the world.
I noticed that heart-disease deaths are actually going up in certain parts of the country, in a reversal of course. Do you know why that is?
There are two things that are happening. Many of the newest cohort that has entered older age in the United States are much more obese than people in the past. It is resulting in a lot of those people getting older and now dying from heart disease. The other thing is—if you look at the paradox in heart disease, which is different from diseases such as cancer—for most heart disease, you actually have very, very effective ways of preventing and treating it. We have good medications, but we’re losing the battle for information and trust. Many people just don’t trust doctors when it comes to the prescriptions or the advice they give.
There’s still a lot of suspicion about very common, but very effective medications such as statins. We still have a lot of problems getting the right medications to the right people.
You’re saying patients don’t trust doctors enough to take the statins they’re prescribed?
[Studies show that even] patients who have already had heart attacks are not taking statins or are not on the appropriate dose of statins. That’s a huge deal. One of the ways this manifests itself is in the so-called “nocebo effect.” The nocebo effect is the evil cousin of the placebo effect. If patients expect harm, or they expect something bad to happen, then that will, in fact, manifest itself in a very real and physical way. One of the things that is most commonly noted about statins is that they [supposedly] cause muscle aches and weakness.
If you look at randomized trials in which patients did not know if they were taking placebo or if they were taking statins, not a single large trial has shown increased prevalence of aches and weakness in patients taking statins. Now that statins are well-known, many patients come in with this idea. They’ve talked to other people or they’ve heard on TV or they’ve read on the internet that statins cause a lot of symptoms. Patients come in overwhelmingly expecting that statins will not make them feel good.
We, as a scientific community, have to convince patients that they can trust us.
Well, and at the same time, you said that experts have historically been very wrong about heart disease. What do you mean by that?
When they first discovered blood pressure, physicians thought that high blood pressure was necessary for blood to reach the most remote or the most difficult-to-reach parts of the body. It was actually the insurance companies who, in millions of their beneficiaries, are collecting data showing that high blood pressure was associated with more people dying. Yet, none of this information was ever followed by the scientific, the cardiology experts of their time.
It took almost decades of almost missionary zeal, not only from the insurance companies, but also from the researchers, to convince the established cardiology community that in fact treating high blood pressure was the right thing to do. Famous cardiologists like William Osler were almost militantly opposed to lowering blood pressure.
At one point, around the second World War, one in two Americans died of high blood pressure, but at that time the leading voices in cardiology actually felt that lowering blood pressure would do more harm than good. It wasn’t until the ’60s, ’70s, and ’80s when this mind-set was fully changed.
The question is, what are the false ideas that we believe today? An expert is someone who has mastery of current knowledge, not of future knowledge. I think we have to find a balance between having people who have expertise, but also understanding that not every time is an established idea the right thing.